<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Session
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Abstract.php 16210 2009-06-21 19:22:17Z thomas $
 * @since      Preview Release 0.2
 */


/**
 * Zend_Session_Abstract
 *
 * @category   Zend
 * @package    Zend_Session
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Session_Abstract
{
	/**
	 * Whether or not session permits writing (modification of $_SESSION[])
	 *
	 * @var bool
	 */
	protected static $_writable = false;

	/**
	 * Whether or not session permits reading (reading data in $_SESSION[])
	 *
	 * @var bool
	 */
	protected static $_readable = false;

	/**
	 * Since expiring data is handled at startup to avoid __destruct difficulties,
	 * the data that will be expiring at end of this request is held here
	 *
	 * @var array
	 */
	protected static $_expiringData = array();


	/**
	 * Error message thrown when an action requires modification,
	 * but current Zend_Session has been marked as read-only.
	 */
	const _THROW_NOT_WRITABLE_MSG = 'Zend_Session is currently marked as read-only.';


	/**
	 * Error message thrown when an action requires reading session data,
	 * but current Zend_Session is not marked as readable.
	 */
	const _THROW_NOT_READABLE_MSG = 'Zend_Session is not marked as readable.';


	/**
	 * namespaceIsset() - check to see if a namespace or a variable within a namespace is set
	 *
	 * @param  string $namespace
	 * @param  string $name
	 * @return bool
	 */
	protected static function _namespaceIsset($namespace, $name = null)
	{
		if (self::$_readable === false) {
			/**
			 * @see Zend_Session_Exception
			 */
			require_once 'Zend/Session/Exception.php';
			throw new Zend_Session_Exception(self::_THROW_NOT_READABLE_MSG);
		}

		if ($name === null) {
			return ( isset($_SESSION[$namespace]) || isset(self::$_expiringData[$namespace]) );
		} else {
			return ( isset($_SESSION[$namespace][$name]) || isset(self::$_expiringData[$namespace][$name]) );
		}
	}


	/**
	 * namespaceUnset() - unset a namespace or a variable within a namespace
	 *
	 * @param  string $namespace
	 * @param  string $name
	 * @throws Zend_Session_Exception
	 * @return void
	 */
	protected static function _namespaceUnset($namespace, $name = null)
	{
		if (self::$_writable === false) {
			/**
			 * @see Zend_Session_Exception
			 */
			require_once 'Zend/Session/Exception.php';
			throw new Zend_Session_Exception(self::_THROW_NOT_WRITABLE_MSG);
		}

		$name = (string) $name;

		// check to see if the api wanted to remove a var from a namespace or a namespace
		if ($name === '') {
			unset($_SESSION[$namespace]);
			unset(self::$_expiringData[$namespace]);
		} else {
			unset($_SESSION[$namespace][$name]);
			unset(self::$_expiringData[$namespace]);
		}

		// if we remove the last value, remove namespace.
		if (empty($_SESSION[$namespace])) {
			unset($_SESSION[$namespace]);
		}
	}


	/**
	 * namespaceGet() - Get $name variable from $namespace, returning by reference.
	 *
	 * @param  string $namespace
	 * @param  string $name
	 * @return mixed
	 */
	protected static function & _namespaceGet($namespace, $name = null)
	{
		if (self::$_readable === false) {
			/**
			 * @see Zend_Session_Exception
			 */
			require_once 'Zend/Session/Exception.php';
			throw new Zend_Session_Exception(self::_THROW_NOT_READABLE_MSG);
		}

		if ($name === null) {
			if (isset($_SESSION[$namespace])) { // check session first for data requested
				return $_SESSION[$namespace];
			} elseif (isset(self::$_expiringData[$namespace])) { // check expiring data for data reqeusted
				return self::$_expiringData[$namespace];
			} else {
				return $_SESSION[$namespace]; // satisfy return by reference
			}
		} else {
			if (isset($_SESSION[$namespace][$name])) { // check session first
				return $_SESSION[$namespace][$name];
			} elseif (isset(self::$_expiringData[$namespace][$name])) { // check expiring data
				return self::$_expiringData[$namespace][$name];
			} else {
				return $_SESSION[$namespace][$name]; // satisfy return by reference
			}
		}
	}


	/**
	 * namespaceGetAll() - Get an array containing $namespace, including expiring data.
	 *
	 * @param string $namespace
	 * @param string $name
	 * @return mixed
	 */
	protected static function _namespaceGetAll($namespace)
	{
		$currentData  = (isset($_SESSION[$namespace]) && is_array($_SESSION[$namespace])) ?
		$_SESSION[$namespace] : array();
		$expiringData = (isset(self::$_expiringData[$namespace]) && is_array(self::$_expiringData[$namespace])) ?
		self::$_expiringData[$namespace] : array();
		return array_merge($currentData, $expiringData);
	}
}
